/*
 * ds18b20.c
 *
 *  Created on: Mar 27, 2017
 *      Author:
 */

#include "ds18b20.h"

//These commands are for internal use only, so they go here. From the DS18B20 datasheet, pages 10-12.

//ROM commands
#define SEARCH_ROM 0xF0
#define READ_ROM 0x33
#define MATCH_ROM 0x55
#define SKIP_ROM 0xCC
#define ALARM_SEARCH 0xEC

//Function commands
#define CONVERT_T 0x44
#define WRITE_SCRATCH 0x4E
#define READ_SCRATCH 0xBE
#define COPY_SCRATCH 0x48
#define RECALL_E2 0xB8
#define READ_PS 0xB4

const unsigned char dallas_crc8_table[256] =
{
    0x00, 0x5e, 0xbc, 0xe2, 0x61, 0x3f, 0xdd, 0x83,
    0xc2, 0x9c, 0x7e, 0x20, 0xa3, 0xfd, 0x1f, 0x41,
    0x9d, 0xc3, 0x21, 0x7f, 0xfc, 0xa2, 0x40, 0x1e,
    0x5f, 0x01, 0xe3, 0xbd, 0x3e, 0x60, 0x82, 0xdc,
    0x23, 0x7d, 0x9f, 0xc1, 0x42, 0x1c, 0xfe, 0xa0,
    0xe1, 0xbf, 0x5d, 0x03, 0x80, 0xde, 0x3c, 0x62,
    0xbe, 0xe0, 0x02, 0x5c, 0xdf, 0x81, 0x63, 0x3d,
    0x7c, 0x22, 0xc0, 0x9e, 0x1d, 0x43, 0xa1, 0xff,
    0x46, 0x18, 0xfa, 0xa4, 0x27, 0x79, 0x9b, 0xc5,
    0x84, 0xda, 0x38, 0x66, 0xe5, 0xbb, 0x59, 0x07,
    0xdb, 0x85, 0x67, 0x39, 0xba, 0xe4, 0x06, 0x58,
    0x19, 0x47, 0xa5, 0xfb, 0x78, 0x26, 0xc4, 0x9a,
    0x65, 0x3b, 0xd9, 0x87, 0x04, 0x5a, 0xb8, 0xe6,
    0xa7, 0xf9, 0x1b, 0x45, 0xc6, 0x98, 0x7a, 0x24,
    0xf8, 0xa6, 0x44, 0x1a, 0x99, 0xc7, 0x25, 0x7b,
    0x3a, 0x64, 0x86, 0xd8, 0x5b, 0x05, 0xe7, 0xb9,
    0x8c, 0xd2, 0x30, 0x6e, 0xed, 0xb3, 0x51, 0x0f,
    0x4e, 0x10, 0xf2, 0xac, 0x2f, 0x71, 0x93, 0xcd,
    0x11, 0x4f, 0xad, 0xf3, 0x70, 0x2e, 0xcc, 0x92,
    0xd3, 0x8d, 0x6f, 0x31, 0xb2, 0xec, 0x0e, 0x50,
    0xaf, 0xf1, 0x13, 0x4d, 0xce, 0x90, 0x72, 0x2c,
    0x6d, 0x33, 0xd1, 0x8f, 0x0c, 0x52, 0xb0, 0xee,
    0x32, 0x6c, 0x8e, 0xd0, 0x53, 0x0d, 0xef, 0xb1,
    0xf0, 0xae, 0x4c, 0x12, 0x91, 0xcf, 0x2d, 0x73,
    0xca, 0x94, 0x76, 0x28, 0xab, 0xf5, 0x17, 0x49,
    0x08, 0x56, 0xb4, 0xea, 0x69, 0x37, 0xd5, 0x8b,
    0x57, 0x09, 0xeb, 0xb5, 0x36, 0x68, 0x8a, 0xd4,
    0x95, 0xcb, 0x29, 0x77, 0xf4, 0xaa, 0x48, 0x16,
    0xe9, 0xb7, 0x55, 0x0b, 0x88, 0xd6, 0x34, 0x6a,
    0x2b, 0x75, 0x97, 0xc9, 0x4a, 0x14, 0xf6, 0xa8,
    0x74, 0x2a, 0xc8, 0x96, 0x15, 0x4b, 0xa9, 0xf7,
    0xb6, 0xe8, 0x0a, 0x54, 0xd7, 0x89, 0x6b, 0x35,
};

void write_scratch_singledrop(onewire_t *ow, uint8_t t_h, uint8_t t_l, uint8_t res)
{
    //reset, presence pulse, skip ROM, write scratchpad command, write data.
    if(onewire_reset(ow)!=0)
    {
        __no_operation();//The temp sensor didn't respond properly, put some error handling here later.
    }
    onewire_write_byte(ow, SKIP_ROM);
    onewire_write_byte(ow, WRITE_SCRATCH);
    onewire_write_byte(ow, t_h);
    onewire_write_byte(ow, t_l);
    onewire_write_byte(ow, res);
    //reset, presence, skip ROM, copy scratchpad
    if(onewire_reset(ow)!=0)
    {
        __no_operation();//The temp sensor didn't respond properly, put some error handling here later.
    }
    onewire_write_byte(ow, SKIP_ROM);
    onewire_write_byte(ow, COPY_SCRATCH); //10ms of strong pullup required if using parasite power; probably not wise to issue other commands to the sensor in this slot...
}

void start_conv_singledrop(onewire_t *ow)
{
    if(onewire_reset(ow)!=0)
    {
        __no_operation();  //The temp sensor didn't respond properly, put some error handling here later.
    }
    onewire_write_byte(ow, SKIP_ROM);
    onewire_write_byte(ow, CONVERT_T);
}

float read_scratch_singledrop(onewire_t *ow) //Reads
{
    uint8_t scratchpad[9]; //Scratchpad contents: Temp LSB, Temp MSB, T_H, T_L, Config Register, reserved x3, CRC
    uint16_t temp_int=0;
    int i=0;
    float temp;
    //reset, presence pulse, skip ROM, read scratch
    if(onewire_reset(ow)!=0)
       {
         __no_operation();  //The temp sensor didn't respond properly, put some error handling here later.
       }
    onewire_write_byte(ow, SKIP_ROM);
    onewire_write_byte(ow, READ_SCRATCH);
    for(i=0; i<9; i++)
        scratchpad[i] = onewire_read_byte(ow);
    if(dallas_crc8((&scratchpad[0]), 9)) //Scratchpad[8] is the checksum; CRC8ing the whole scratchpad should return 0.
        {
        __no_operation(); //Put error handling here; the data didn't arrive intact.
        }
    temp_int = (float)(((scratchpad[1] & 0x07)<<8) | scratchpad[0]);
    temp = temp_int / 16.0; //2^-4 granularity. Fixed-pt will get spit out as an integer, so cast to float and divide by 2^-4 for the decimal value.
    if(scratchpad[1] & 0xF8)
        temp *= -1;
    __no_operation(); //for debugger
    //PB's expecting a float, so that's what we convert to.
    return temp;
}

uint8_t dallas_crc8(uint8_t *data, int size)
{
uint8_t crc=0;
uint8_t *p = data;
uint8_t *end = (uint8_t*)((int)p + size);
while(p < end)
    crc = dallas_crc8_table[crc ^ *(p++)];
return crc;
}


